Biomedical subjects
Publications and source records attributed to M Weiss.
Yersinia enterocolitica agglutinating antibodies were present in 42% of 36 patients with thyroid disease and in none of 77 control subjects. Since the frequency of Yersinia infections in Israel is low, the association of thyroid diseases with Yersinia antibodies is of particular interest. The significance of this finding is discussed in view of some recent observations.
Cross reactions investigated by double immunodiffusion and by immunoelectrophoresis between human plasma and plasma of 5 animal species using a specific rabbit antiserum against human At-III revealed antigenic relationships between the antithrombins of these species. But the quantitative measurements of At-III by immunologic methods (electro-immunodiffusion and radial immunodiffusion), using the rabbit antiserum, were not possible in common laboratory animals, except in baboons.
Ascending paralysis developed in 3 dogs, 12 to 14 days following inoculation with a modified live virus, chicken embryo origin, low egg passage, Flury strain rabies vaccine. The paralysis began in the inoculated limb but rapidly involved both hindlimbs. Partial paresis of the forelimbs was seen several days following the hindlimb paralysis in all 3 dogs, and in 1 of these dogs the infection ascended rapidly to the brain as well. Two of the dogs recovered within 1 and 2 months, respectively, but the 3rd dog died within 5 days of the onset of paralytic signs. The fatal case was complicated by naturally acquired coincidental distemper. Serologic studies in 2 dogs and virus isolation from the 3rd dog indicated that rabies virus was the cause of the paralysis in 2 of the dogs and contributed to the disease syndrome in the 3rd dog. Virus could not be isolated from the saliva of CSF of the 2 surviving dogs. The virus isolated in the fatal case appeared to have some of the characteristics of the vaccine virus, as determined by its behavior in mice, cell culture, and embryonating chicken eggs and by its failure to produce Negri bodies in the brain of the infected dog.
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We have performed restriction endonuclease mapping to examine the linear organization of the ovalbumin gene in chromosomal DNA. Treatment of genomic DNA with restriction endonucleases that do not cleave the ovalbumin mRNA sequence results in the generation of multiple DNA fragments capable of annealing with ovalbumin-specific probes in molecular hybridization reactions. These data strongly suggest that the linear order of DNA sequences coding for ovalbumin is interrupted by at least two intragenic DNA spacers absent from the corresponding RNA. At least one of these spacer sequences interrupts the coding sequence; therefore the chromosomal ovalbumin gene is not colinear with its translational product. We can discern no difference in the sequence organization about this gene in producer and nonproducer somatic cells, suggesting that the presence of intragenic spacers does not reflect that transcriptional activity of this gene. Furthermore, profiles obtained for gametes are identical to those observed for somatic cells, indicating that significant translocation during development is not responsible for the generation of this split sequence. Divergence of the intragenic spacer, however, is observed between individual chickens; thus multiple alleles may exist for this gene that are identifiable by differences in the organization of spacer with no apparent phenotypic evidence for their presence.
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A specific dosage schedule is designed for the case of multiple dosing with the aim of achieving the desired steady-state blood level in a predetermined time interval. The method is based on the administration of nonuniform doses at uniform dosage intervals during the saturation time. To calculate the doses a nonlinear equation must be solved. The theory is illustrated by a quantitative example (digitoxin).
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The autoregulation behaviour of the coronary circulation was studied on an isolated Langendorff-heart of rabbit. Static pressure-flow curves were recorded for the normal and maximally dilated vascular system. For analyzing the dynamics of autoregulation of the flow to pressure jumps within the autoregulation range was measured. Modelling was performed by means of the linear system theory, assuming first-order transfer functions for the contraction and dilatation process co-acting in the regulation. The system parameters were determined in the time-range by adapting a bi-exponential function to the measured data. For the dilatation reaction following pressure fall a mean time constant of 5.4 s was measured, while a time constant of 146.8 s was found for the counterregulation (constriction). These events are discussed with regard to possible further studies on the pharmacology of coronary regulation.
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The local quantity of the contrast excretion depends on the filtration rate and the plasma level. Since the latter is influenced by dosage and kind of application from this result immediate practical consequences for the excretion urography, for which at present a large dose and the bolus injection are preferred.
Relaxin concentrations during pregnancy and parturition were measured in tissue specimens of the uterine cervix of 27 women in childbearing age. During pregnancy relaxin levels increase from 0.4 guinea pig unit (GPU) to 0.94 GPU/mg soluble tissue protein. Already during parturition (0.41 GPU) and immediately post partum (0.39 GPU) the hormone concentrations have dropped back to normal. It appears that the biochemical changes which occur in the connective tissue of the uterine cervix during pregnancy and parturition are influenced by relaxin. Experimental animals were taken to show if relaxin acts by activation of collagenolytic enzymes. In the mouse a rise in the activity of collagen-peptidase and of the inhibitor of collagen-peptidase in plasma was found after subcutaneous injections of relaxin. The addition of human cervical tissue extracts resulted in an increase of enzyme-activation (even higher than could be expected of the hormone concentrations of the individual extracts). The highest levels of the enzyme were found after injections of extracts from cervical tissue specimens of parturient women.
A simple procedure for the purification of the peptide hormone relaxin is described. It allows prepare with good yield highly purified relaxin of an activity of 700 GPU/mg protein. For the first time ion-exchange chromatography by Amberlite IRA-410 and subsequent gel filtration on sephadex G-25 fine were used as purifications steps.
To test whether or not the characteristics of the adult heart-rate reflect the condition of the central nervous system (as they seem to do in the fetus), ten patients with neurological deficits of acute onset were studied. No patients had received drugs and none was hypoxic. The findings indicate that the normal cyclic changes in heart-rate are reduced in the presence of severe brain damage. Variability decreases rapidly if intracranial pressure rises, and the rate of return of variability reflects the subsequent state of neuronal function, even when intracranial pressure has been restored to normal. In this limited setting, then, it appears that heart-rate variability may reflect the functional state of the central nervous system.
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